Examples of liquid crystal displays (LCDs) include direct view displays and projection displays (e.g., rear and front projection LCDs). Many LCD projection displays include a LCD microdisplay that modulates light from a light source to produce an image which is then projected onto a screen using an optical projection system. One type of LCD microdisplay is formed on a silicon substrate. Such LCD microdisplays are commonly referred to as Liquid Crystal on Silicon (LCoS) displays.
Many types of full color LCDs include arrays of color filters corresponding to the display's pixels. A display that produces color images by modulating the red, green, and blue content of each display pixel, for example, typically includes a red, green, and blue subpixel, where each subpixel has a color filter that selectively absorbs/transmits a portion of the visible spectrum. In many types of direct view displays, for example, a red subpixel includes a color filter that absorbs radiation in the blue and green portions of the visible spectrum, while transmitting radiation in the red portion of the visible spectrum. The red subpixel modulates the “red” content of the pixel by modulating the amount of light reflected or transmitted by the pixel, depending upon whether the display is a reflective or transmissive display. Similarly, the “green” and “blue” content of the pixel is controlled by modulating the amount of light reflected or transmitted by the green and blue subpixels, respectively.
Color filter arrays are generally used in displays that spatially synthesize color imagery. Alternatively, certain types of display sequentially modulate different colored light, where the human visual system fuses images of different color to provide the colored imagery. For example, projection displays using extremely fast light modulators (e.g., Digital Micromirror Devices) can be used in conjunction with a rotating color wheel (e.g., a rotating device that sequentially filters a light source providing light to the modulator) to provide a full color image. Other examples of full color projection displays overlap images from multiple display panels, each image being composed of a different color, to provide a full color image.
In general, for displays with spatially synthesized color, color filter arrays should include an element corresponding to each subpixel in the display. The shape of the filter elements should correspond to the shape of the pixel electrodes in the display. Furthermore, the filter array should be precisely aligned with the pixel electrodes. Accordingly, efficient and precise manufacturing and assembly techniques are desirable for producing color filter arrays and registering the arrays to the other portions of a display.